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R. JOY. STEAM BOILER.

No Model.)

No. 520,962. Patented June 5, 1894.

OOOOO WITNESSES: INVENTOR 7% I 5 NATIONAL umammma coMPAuv A R N UNiTRDSTATES PATENT FFICE.

ROBERT JOY, OF OSWEGO, NEW YORK, ASSIGNOR TO THOMSON iiiuesroRn,

' or sAME PLACE.

STEAM-=BOILER.

SPECIFICATION forming part of Letters Patent No. 520,962, dated une 5, 1894.

Application filed March 16, 1893. Serial No. 466,274. (No model.)

To all whom itmcry concern:

Be it known that I, ROBERT JOY, of Oswego, in the county of Oswego, inthe State of New York, have invented new and useful Improvements inSteam-Boilers, of which the following, taken in connection with theaccompanying drawings, is a full, clear, and exact description.

This invention relates to the class of steam boilers which aredesignated return line boilers and has more particularly reference tothat species in which the bridge-wall is movable lengthwise of theboiler to vary the size of the fire-box or grate-surface.

The object of my present invention is to simplify the construction ofthe adjustable boiler furnace and to combine the same in a simple andeconomical manner with a boiler formed with water-legs and a water-backand thus combine simplicity of construction with increased efficiency ofthe boiler; and to that end the invention consists in the improvedconstruction and combination of parts hereinafter described andspecifically set forth in the claim.

In the annexed drawings, Figure 1 is a vertical longitudinal sectionthrough the center of a boiler embodying my invention, and Fig. 2 is aVertical transverse section on line :0, 00, in Fig. 1.

Similar letters of reference indicate corresponding parts.

13-- represents the horizontal flue-boiler which is much shorter thanordinary boilers of that class.

O- denotes the fire-box which extends from the front end of the boilerbeyond the rear end thereof as shown in Fig. 1 of the drawings, and D=denotes the combustionchamber which is extended vertically from the rearend of the fire-box. The front of the fire-box is provided with thefeed-door 'O'- through which to introduce the fuel. The products ofcombustion pass from the fire-box up in the combustion chamber "-D- andthence pass through the flues 'jto the smoke-box I- on the front end ofthe boiler. Said boiler with its water jacketed fire-box and combustionchamberl construct as follows to wit:

The shell of the boiler proper =B-= is preferably cylindrical and theupper half thereof I extend beyond the rear flue-sheet b' as shown at B-in Fig. 1 of the drawings. The Vertical outer side-plates aaextend fromthe base of the boiler to the sides of the boiler-shell and itsaforesaid rearward extension and are joined thereto. The outerback-plate --'-g-. extends from the top of the boiler shell extension Bto the base of the boiler. The front flue-sheet bextends likewise to thebase of the boiler. The inner front sheet e- I attach to the lower halfof the boiler-shell and join it to the base of the aforesaid flue-sheetextension. The inner side-plates f-f- I attach to the lower portion ofthe boiler shell and to'the bases of the outer side-plates -a-a. Therear portions of said inner side-plates extend vertically and are unitedwith the crown-sheet d-- of thecombustion chamber -D- and the inner backplate z'. crown-sheet, inner side-plates fand I join to said 1 base ofthe outer back-plate -g. Said boiler is thus formed with water-legs anda waterback and without any bottom plate, and rests with the bases ofthe water-legs and water- -back directly upon a suitable floor which isin a uniform plane and constitutes the floor of the ash-pit and floor ofthe combustionchamber D-. Upon this floor I erect the bridge-wall O-which is formed preferably of cast iron and with a forwardly andrearwardly extending foot or base by which it is sustained in an uprightposition and movable longitudinally on the aforesaid floor, and is thusadapted to be set either under the main portion -'-B- of the boiler, orback of the same a greater or less distance from the rear flue-sheet b'-to enlarge or diminish the throat "T over the top of the bridge-wall asmay be required for the proper combustion of different fuels to be usedfor heating the boiler.

. *O represents the adjustable bridgewall, which is vertical andpreferably formed of cast-iron and with a forwardly and rearwardlyextending foot or base by which it is seated upon the bottom of theash-pit and is thus properly sustained in its upright positionindependent of the grate as clearly shown in Fig. 1 of the drawings.

When coal is to be used for fuel I form the bridge wall with a ledge-tfor supporting the rear ends of the grate bars -h-, the

front ends of which are supported on an angle-iron --tfastened to theinner front plate -e. Immediately above the grate the front of thebridge-wall is formed with a recess Z in which is secured thefire-bricklining -Z'-- to protect the bridge wall from melting heat. Thetop of the bridge wall I preferably form segmental and parallel with thebottom portion of the boiler shell. In this manner I obtain a segmentalthroat T for the passage of the products of combustion from the bottomof the rear end of the boiler to the combustion chamber -D. Saidproducts of combustion are thuscaused to more eflt'ectually impinge theboiler and increase its efiiciency.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is-

The combination of the return line boiler B- formed with the combustionchamber D- and with water legs and a water-back 25 and seated upon afloor extending in a uniform plane under the boiler and aforesaidcombustion chamber, the bridge-wall 0-- sustained on said floor movablelongitudinally, and adapted to enlarge or diminish the 0 throat -T- andprovided with the ledge t and the grate-bars hsupported at 2 their rearends on said ledge substantially as described and shown.

In testimony whereof I have hereunto 35

